Recently some news have appeared in which doubts about the effectiveness of the so-called “cloth masks”. Before going into the matter of their effectiveness, it should be clarified that all masks are made of fibers (or threads), which form fabrics. Therefore, technically, all masks are made of cloth.
When we look at them with the naked eye, some of them may look like plastic or paper. However, with a low magnification magnifying glass we could easily see that they are made up of tangled fibers forming a fabric. If they did not have this structure, they would have insufficient porosity to facilitate breathing.
What really are “cloth masks”?
The masks can be classified in two different ways: according to the number of uses (single use or reusable) or according to the recommended end use (PPE, surgical and hygienic).
Surgical and PPE are generally single-use. The hygienic ones are usually reusable up to a certain number of washes.
From now on, when we talk about reusable hygienic masks, we will refer to those known as “cloth masks”. These masks are regulated by a standard and must meet two basic technical requirements: filtration efficiency and breathability.
Masks that do not comply with these regulations are considered “homemade”, they do not follow any regulations and, therefore, we are not aware of their level of protection against the virus.
What matters is the level of protection
The classification of the masks according to the degree of protection can be related to the filtration capacity. Thus, they are distinguished:
- Masks type EPI : classified as FFP1, FFP2 and FFP3 according to their level of filtration of particles in suspension (78%, 92% or 98% respectively).
- Type I or II surgical masks : with minimum bacterial filtration efficiency levels of 95% and 98% respectively.
- Hygienic masks: which can be single use or multiple uses (reusable), with minimum levels of bacterial filtration of 95 and 90% respectively.
It is very important to clearly understand the meaning of filtration degrees and how they are being measured.
In EPI-type masks, the filtration capacity of particles greater than 0.3 microns is measured, while in surgical and hygienic masks, the bacterial filtration efficiency (particles greater than 3 microns) is determined. Therefore, the EPI type have a high filtration capacity against particles about 10 times smaller than the rest of the masks.
A high bacterial filtration capacity of particles larger than 3 microns does not guarantee that a high percentage of smaller particles will filter. A mask may be filtering a high percentage of bacteria but not suspended viruses.
However, it must be taken into account that the virus is transmitted by aerosols (size less than 5 microns) but also by droplets, which are much larger.
From all the aforementioned, a first obvious conclusion could be obtained: EPI-type masks (FFP2 or FFP3) are those that provide us with the best protection against aerosols containing viruses.
These masks are especially recommended in small, poorly ventilated spaces with a high viral load. Healthcare personnel exposed to these extreme conditions is the ideal user profile for these masks. This is advised by the Ministry of Industry, Commerce and Tourism.
Do reusable hygienic masks protect us?
It must be assumed that no mask can guarantee 100% protection. As we have seen, even the most effective (EPI) have filtration levels below 100%. That is why it is very important to protect ourselves with other complementary measures such as distance and hand washing.
However, that a mask does not protect us 100% does not mean that it is not useful or that it does not protect us in a high percentage.
Depending on the context, one type of mask or another will be more advisable. Thus, it is recommended that healthy people wear hygienic masks, sick people surgical ones, and those in contact with the virus PPE.
Does this recommendation make sense? From our point of view, yes. Depending on the situation in which we find ourselves, there will be a greater or lesser concentration of virus particles and their spread will be predominantly aerosols or droplets.
In some cases, it will be more important to protect others from the droplets that we emit when we speak, cough or sneeze than from possible aerosols.
In places where the probability of particle concentration is very low ( ventilated spaces, with an uninfected population that uses a mask and maintains a safe distance ), protecting ourselves with a surgical or hygienic mask may be sufficient.
On the other hand, in some cases, the filtration levels of reusable surgical and hygienic masks are similar. Therefore, reusable hygienic masks can offer us similar levels of safety to surgical ones.
Hygienic, certified and well used masks
If we consider using a reusable hygienic mask to protect ourselves, we must ensure that it complies with current regulations. Consumers must have the guarantee that the products offered for sale comply with said regulations.
Just as it is crucially important to know the degree of protection of a mask, it is also crucial to ensure that it is used correctly. It is useless to put on a high-filtration EPI mask if it does not fit well on the face. It could even be being less effective than, for example, a well-fitted hygienic mask.
Correct cleaning and disinfection of the masks will also be important. For this, the manufacturer’s recommendations must be followed or, if they are not provided, the recommendations of the Ministry of Health. In most cases, a normal wash cycle between 60 ℃ and 90 ℃ will suffice.
Thus, if we choose a certified reusable hygienic mask and use it correctly, it will serve to prevent the release and spread of the SARS-CoV-2 virus. In addition, they are more comfortable and aesthetically pleasing masks than surgical or PPE. They also contribute to the development and consolidation of the Spanish textile industry. By using them, we will help boost our economy.
Using reusable hygienic masks is more sustainable
Taking into account that a surgical mask weighs approximately 3 grams, if each Spaniard uses 3 masks a week, we would generate 1,710 tons of waste per month.
Therefore, using reusable hygienic masks contributes significantly to reducing waste generation.
Furthermore, if their collection is properly managed (including a previous disinfection system), they could be recycled and converted into new textile products.
Mónica Ardanuy, Professor of Textile Engineering, Polytechnic University of Catalonia – BarcelonaTech; Diana Cayuela, Professor of Textile Engineering, Polytechnic University of Catalonia – BarcelonaTech; Enric Carrera i Gallissà, Director of the Textile Research and Industrial Cooperation Institute of Terrassa (INTEXTER). UPC, Polytechnic University of Catalonia – BarcelonaTech and José Antonio Tornero,, Polytechnic University of Catalonia – BarcelonaTech
This article was originally published in The Conversation. Read the original.
